It seems that the guys behind the original 2012 mod are back and now working on a new version of Mafia 2's Multiplayer Mod after a long hiatus.

I hope this one will succeed. Mafia 2 would be great with multiplayer as long as some gamemodes such as racing or a fight club (like what was planned in the original) are available since Empire Bay really doesn't have that much to do if its with other players.

They are already there since 2015
You should be around discord servers to be more informed. There are already 3 major servers about Mafia. Ill put their link here: https://discord.gg/yp88BVd_________________